Equipment for mechanical machining, in particular for the turning and drilling of light alloy wheels

ABSTRACT

Equipment for mechanical machining, especially the turning and drilling of mechanical workpieces, such as light alloy wheels and the like, includes at least one turning unit with a double chuck to support the workpieces being machined and a turning head designed to work in association with one or other of the chucks alternately. At least one first workpiece loading/unloading device can be used for moving the workpieces being machined on one or other of the chucks so as to bring about loading/unloading of the workpieces from one of the chucks at the same time as mechanical machining is being carried out on the other chuck. The equipment further includes at least one drilling unit operatively associated with the turning unit and including at least one first drilling head combined with at least one corresponding first workpiece-holding device and at least one second device for loading/unloading parts to move parts being machined in the drilling unit. The first and second loading/unloading devices are further incorporated into the equipment to move the parts being machined away from and towards one or the other of the turning and drilling units so that mechanical machining in the drilling and turning unit takes place at the same time as the operations of loading and unloading workpieces onto and from the equipment.

This application is a U.S. National Phase Application of PCTInternational Application PCT/IT2002/000741.

TECHNICAL SCOPE

This invention relates to equipment for mechanical machining, and inparticular for turning and drilling light alloy wheels.

TECHNICAL BACKGROUND

In the specific technical field of the manufacture of light alloywheels, of aluminium alloy in particular, the mechanical machining whichis mainly required on these metal parts comprises turning and drillingin accordance with predetermined working cycles.

These working cycles generally comprise rather short cycle times, of theorder of a few minutes, in which the effect of the time during whichtools are moved (otherwise known as the “changeover time”) and the timefor loading/unloading the workpieces is rather substantial in comparisonwith the actual time for which the machine tools are working in theoverall cycle time. By way of example it may be noted that this mayamount to even 30% and more of the machining cycle time in the case ofcycle times of the order of approximately 1 minute.

It is also obvious that as the specified cycle times are reduced (as aresult, for example, of reduced working times for the removal ofturnings), because the changeover and loading/unloading times remainsubstantially unchanged this effect increases in proportion, penalizingthe overall productivity of the machining equipment.

BRIEF SUMMARY OF THE INVENTION

A principal object of the invention is to provide machining equipmentwhich has been specially designed for the drilling and turning of lightalloy wheels with characteristics which drastically reduce the effect ofdead times, which are understood to be the times involved in accessoryoperations (changeover times and workpiece loading/unloading times),during which no mechanical machining with the removal of turnings takesplace, in comparison with overall cycle times, with a consequentadvantageous increase in the overall productivity of the equipment.

This object and others which will appear below in the description areaccomplished by equipment for mechanical machining constructed inaccordance with the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Other advantages and characteristics of the present invention willbecome clear from the following detailed description which is given withreference to the appended drawings which are provided purely by way ofnon-limiting example and in which:

FIG. 1 is a diagrammatical front elevation view of mechanical machiningequipment according to the invention,

FIG. 2 is a diagrammatical view in plan of the equipment in FIG. 1,

FIG. 3 is a diagrammatical side elevation view of the equipment in thepreceding figures.

PREFERRED EMBODIMENT OF THE INVENTION

With reference to the figures mentioned, 1 indicates as a wholemechanical machining equipment for turning and drilling wheels 2 oflight alloy, especially aluminium alloy, constructed in accordance withthis invention.

Equipment 1 comprises a turning unit 3 combined with a drilling unit 4,the working areas of which are indicated by A and B respectively in FIG.2 (with a double dotted and dashed line).

Turning unit 3 comprises a base 5 on which is provided a pair of chucks6, 7 with corresponding axes of rotation X, X′ to support workpieces(wheels 2) undergoing machining and a turning head 8 designed to work inassociation with one or other of chucks 6, 7 alternately. Moreparticularly, head 8 comprises an erect upright 9 from base 5 on whichare provided guide and control means for a tool-holding slide 10 whichcan make guided movements away from and towards chucks 6, 7 along adirection parallel to an axis Y perpendicular to axes X, X′ so thatturning head 8 can work in the area of one or other of chucks 6, 7alternately.

Chucks 6, 7 are also served by a single slide for rotation of theworkpiece being machined. 11 indicates a first workpieceloading/unloading device, which forms part of a system for moving theworkpieces and extends within working areas A and B through a magazine12 from which wheels 2 requiring machining are taken and a station 13for unloading machined wheels 2.

Conveniently the movement system is constructed with vertical uprights14 which are designed to support a beam 15 lying above working units 3,4 and incorporating guide means to guide device 11 in the correspondingworking area. Beam 15 extends longitudinally between magazine 12 andunloading station 13.

Device 11 comprises an arm 16 which can move transversely in thedirection of movement of the device along beam 15, approaching/movingaway from chucks 6, 7 for the operations of loading/unloading wheels 2from turning unit 3. Preferably arm 11 a has a handling device 17 at oneend which is designed to seize wheels 2.

Drilling unit 4, associated with working area B, is operativelyassociated with turning unit 3 and comprises a corresponding base 18 onwhich first and second workpiece-holding devices, indicated by 19 and 20respectively, are located. Drilling unit 4 also comprise a pair ofdrilling heads 21, 22, each of which is provided with a correspondingtool-holding turret 21 a, 22 a capable of performing at least threeworking movements in three corresponding controlled axes and associatedwith a corresponding tool magazine, which is not shown. Heads 21, 22 areincorporated in drilling unit 4 so that either each can work with itscorresponding workpiece-holding device or both can work on the samedevice in order in this second situation to carry out corresponding andseparate drilling operations in one working cycle in which one head isbeing fitted with a tool to carry out subsequent drilling operations atthe same time as the other drilling head is actively engaged inmachining wheel 2.

It is also provided that drilling heads 21, 22 are further incorporatedinto working unit 4 so as to carry out different drilling operations inone working cycle on a wheel 2 supported in one of devices 19, 20 at thesame time as the workpiece is being loaded onto/unloaded from the otherdevice.

In this respect the equipment comprises a second workpieceloading/unloading device, indicated by 23, which is structurally andfunctionally identical to device 11, and correspondingly incorporates anarm 24 with a handling member 25 for grasping wheels 2. In the same wayas in the case of device 11, device 23 is guided along beam 15 to movethe wheels in the operations of loading/unloading from workpiece-holdingdevices 19, 20 and taking wheels 2 from magazine 12 and transferringthem to the working area appropriate for turning operations, and viceversa.

Conveniently devices 11, 23 are incorporated into equipment 1 for movingworkpieces (wheels 2) which are being machined from and towards one orother of machining units 3, 4 so that the mechanical operations ofdrilling and turning take place at the same time as the operations ofloading/unloading from the workpiece-holding devices and the chucks, andat the same time as the stages in which the machining heads are fitted.

In operation, initially with reference to working area A in whichturning is performed, it is provided that while turnings are beingremoved from the wheel supported in one of chucks 6, 7 a workpiece isloaded onto and unloaded from the other chuck at the same time usingdevice 11. In this way the stages of acceleration/deceleration of one ofthe chucks before and after the stages of tool fitting takes place in aconcealed time during which turnings are at the same time removed fromthe piece gripped in the other chuck. It follows that chucks 6, 7 arenot therefore substantially affected by dead times, by which times aremeant the times required for loading/unloading workpieces, the times foraccelerating/decelerating the chuck and the times for changing tools.

Similarly, with reference to working area B where drilling is performed,drilling operations are carried out on a wheel secured on one of devices19, 20 while a machined workpiece is at the same time loadedonto/unloaded from the other device 19, 20 using means 11, 23. Again inthis case therefore dead times are concealed in that theloading/unloading and tool-fitting times for one device are at the sametime effective machining time with the removal of turnings for the otherdevice. It is provided that the drilling operations in one cycle areperformed by only one of the two drilling heads or both. In the lattercase, while one of heads 19, 20 performs the drilling operation, theother head is fitted with a new tool so that it can perform the nextdrilling operation.

When both heads 19, 20 complete the drilling operation specified in theworking cycle, they are moved in the direction of the adjacentworkpiece-holding device in order to carry out a further machiningcycle.

It will be noted that in equipment 1 workpieces can be machined withappropriate checks first in turning unit 3 and then in drilling unit 4or vice versa, the machining heads and the loading/unloading devicesbeing designed to work in both ways indicated.

It will also be noted that the use of two drilling heads incorporatedinto machining unit 4 makes it possible to use tool-changing mechanismsof a substantially simple type with every advantage in ease of handlingand control of the machining unit.

The invention thus achieves the objects specified, providing manyadvantages in comparison with known solutions.

Firstly, the equipment according to the invention makes possible asubstantial reduction in dead times during the working cycle, in themeaning of the term indicated above, with an advantageous increase inproductivity in comparison with known applications.

In particular the equipment according to the invention makes it possibleto achieve a drastic reduction in the effect of loading/unloading timesand the time for tool fitting and movement of the tool/workpiece-holdingtable within the overall cycle time so that cycle times are not governedby these accessory operations in relation to the actual time for theremoval of turnings specified in the working cycle.

Furthermore, as a result of the features of the equipment according tothe invention, the machine tools provided in the machining units are notsubjected to machine shutdowns for operations other than actualmachining operations with the removal of turnings, with a consequentmaximization of productivity.

1. Equipment for mechanical machining of workpieces, the equipmentcomprising: at least one turning unit with double chucks to support theworkpieces being machined and a turning head designed to workalternately in association with one or other of the double chucks, atleast one first workpiece loading/unloading device for moving theworkpieces being machined to one or other of the double chucks so thatworkpieces are loaded/unloaded from one of the double chucks at the sametime as mechanical machining is being performed on the other of thedouble chucks, at least one drilling unit operatively associated withthe turning unit and including at least one first drilling head combinedwith at least one corresponding first workpiece-holding means, at leastone second workpiece loading/unloading device for moving workpiecesbeing machined in the at least one drilling unit, the first and secondworkpiece loading/unloading devices being further incorporated into theequipment to move the workpieces undergoing machining towards and awayfrom one or other of the turning and drilling units so that mechanicalmachining in the drilling and turning units takes place at the same timeas the operations of loading and unloading workpieces onto and from theequipment.
 2. The equipment according to claim 1, comprising in thedrilling unit at least one second drilling head and at least one secondworkpiece-holding means, the first and second drilling heads beingincorporated into the drilling unit in such a way as to carry outcorresponding separate drilling operations in one working cycle on aworkpiece supported on one of the workpiece-holding means while at thesame time workpiece loading/unloading movements are being performed inrelation to the other workpiece-holding means.
 3. The equipmentaccording to claim 2, in which the drilling heads are equipped withcorresponding tool magazines so that during stages in which machining iscarried out by one of the heads the other head is at the same time beingfitted with tools to carry out subsequent drilling operations.
 4. Theequipment according to claim 3, in which guide means are provided for atleast one of the drilling heads along three corresponding controlledworking axes.
 5. The equipment according to claim 3, in which the atleast one turning head comprises a corresponding tool-holding slideguided so as to move away from and towards the chucks for alternatemachining at one or other of the chucks.
 6. The equipment according toclaim 3, in which the first and second workpiece loading/unloadingdevices are guided along the turning and drilling units between amagazine from which workpieces are picked up for machining and anopposite station for unloading workpieces machined in the equipment. 7.The equipment according to claim 2, in which guide means are providedfor at least one of the drilling heads along three correspondingcontrolled working axes.
 8. The equipment according to claim 7, in whichthe at least one turning head comprises a corresponding tool-holdingslide guided so as to move away from and towards the chucks foralternate machining at one or other of the chucks.
 9. The equipmentaccording to claim 7, in which the first and second workpieceloading/unloading devices are guided along the turning and drillingunits between a magazine from which workpieces are picked up formachining and an opposite station for unloading workpieces machined inthe equipment.
 10. The equipment according to claim 2, in which the atleast one turning head comprises a corresponding tool-holding slideguided so as to move away from and towards the chucks for alternatemachining at one or other of the chucks.
 11. The equipment according toclaim 2, in which the first and second workpiece loading/unloadingdevices are guided along the turning and drilling units between amagazine from which workpieces are picked up for machining and anopposite station for unloading workpieces machined in the equipment. 12.The equipment according to claim 1, in which the at least one turninghead comprises a corresponding tool-holding slide guided so as to moveaway from and towards the chucks for alternate machining at one or otherof the chucks.
 13. The equipment according to claim 12, in which thefirst and second workpiece loading/unloading devices are guided alongthe turning and drilling units between a magazine from which workpiecesare picked up for machining and an opposite station for unloadingworkpieces machined in the equipment.
 14. The equipment according toclaim 1, in which the first and second workpiece loading/unloadingdevices are guided along the turning and drilling units between amagazine from which workpieces are picked up for machining and anopposite station for unloading workpieces machined in the equipment. 15.The equipment according to claim 14, in which the workpieceloading/unloading devices are conducted along a guide supported byvertical uprights and lying above the turning and drilling units formoving the workpieces being machined from and towards the drilling andturning units between the magazine from which the workpieces are pickedup and the station at which the workpieces are unloaded from theequipment.
 16. The equipment according to claim 1, wherein theworkpieces are alloy wheels.
 17. Equipment for mechanical machining ofworkpieces, the equipment comprising: at least one turning unit with atleast a pair of chucks to support the workpieces being machined andrespective turning heads designed to work in association with thecorresponding chucks, at least one first workpiece loading/unloadingdevice for moving the workpieces being machined to one or other of thechucks so that workpieces are loaded/unloaded from one of the chucks atthe same time as mechanical machining is being performed on the otherchuck, at least one drilling unit operatively associated with theturning unit and including at least one first drilling head combinedwith at least one corresponding first workpiece-holding means, at leastone second workpiece loading/unloading device for moving workpiecesbeing machined in the at least one drilling unit, the first and secondworkpiece loading/unloading devices being further incorporated into theequipment to move the workpieces undergoing machining towards and awayfrom one or the other of the turning and drilling units so thatmechanical machining in the drilling and turning units takes place atthe same time as the operations of loading and unloading workpieces ontoand from the equipment.
 18. The equipment according to claim 17, whereinthe workpieces are alloy wheels.
 19. Equipment for mechanical machiningof workpieces, the equipment comprising: at least one turning unit withdouble chucks to support the workpieces being machined and a turninghead designed to work alternately in association with one or other ofthe double chucks, at least one first workpiece loading/unloading devicefor moving the workpieces being machined to one or other of the doublechucks so that workpieces are loaded/unloaded from one of the doublechucks at the same time as mechanical machining is being performed onthe other of the double chucks, at least one drilling unit operativelyassociated with the turning unit and including i) at least one firstdrilling head combined with at least one corresponding firstworkpiece-holding means and ii) at least one second drilling head and atleast one second workpiece-holding means, the first and second drillingheads being incorporated into the drilling unit in such a way as tocarry out corresponding separate drilling operations in one workingcycle on a workpiece supported on one of the workpiece-holding meanswhile at the same time workpiece loading/unloading movements are beingperformed in relation to the other workpiece-holding means, at least onesecond workpiece loading/unloading device for moving workpieces beingmachined in the at least one drilling unit, the first and secondworkpiece loading/unloading devices being further incorporated into theequipment to move the workpieces undergoing machining towards and awayfrom one or other of the turning and drilling units so that mechanicalmachining in the drilling and turning units takes place at the same timeas the operations of loading and unloading workpieces onto and from theequipment.